textproduct: Rapid City

KEY MESSAGES

- Active pattern persists through the weekend with daily chances of showers and thunderstorms.

- Increased severe weather potential Sunday through Tuesday, although details remain uncertain.

UPDATE

Issued at 1122 PM MDT Fri Aug 14 2026

Going forecast in pretty good shape. Upper ridge over the southeast CONUS will slowly move west and flatten into early next week. This puts the CWA under southwest, then westerly flow aloft. A plethora of shortwaves will move through, each bringing showers/tsra at times. Increasing buoyancy/shear by Sunday/Monday (possibly Tuesday) will result in increasing chances for active/severe convection. Details still to be ironed out.

DISCUSSION

(This Evening Through Friday) Issued at 115 PM MDT Fri Aug 14 2026

Active southwest upper level flow continues with southeasterly surface flow. Surface dew points range from the upper 50s in Wyoming and the Black Hills to mid 60s across western South Dakota. Low clouds eroded through the morning with surface heating driving temperatures into the upper 70s and low 80s. SPC mesoanalysis and the 18z KUNR RAOB show 500-1000 J/kg MLCAPE across the area with effective bulk shear around 30 to 40 knots. Scattered convection is trying to develop across NW SD and NE WY, although coverage may be limited until a shortwave arrives later this afternoon and early evening. Widespread severe weather is not anticipated, however isolated strong to severe storms are possible given the instability and shear parameter space.

Daily chances for showers and thunderstorms will persist through the weekend into early next week. Upper level flow is forecast to become more zonal/northwesterly early next week into mid week. Severe potential increases Sunday and Monday with ample instability and shear around 35 to 50 knots. Severe potential may stretch into Tuesday, but timing of the wave and location of the surface front remain uncertain.

Longer range guidance shows a strong area of high pressure building over the SW US by end of next week into the weekend with temperatures trending warmer for our area.

AVIATION

(For the 12Z TAFS Through 12Z Sunday Morning) Issued At 521 AM MDT Sat Aug 15 2026

Isolated to scattered showers and storms will be possible today, mainly across the southwest half. Transient MVFR conditions are expected around any heavier precipitation cores.

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...None.